Method and mobile station for automatic creation of talk group

ABSTRACT

A method of automatic creation of a talk group in a wireless radio communication system comprising a plurality of mobile stations, said method comprising the steps of: transmitting by a first mobile station an emergency message containing at least its ID and localization data; transmitting by other mobile stations their IDs and localization data in response to said emergency message; creating said talk group by selecting those mobile stations which transmitted their IDs and localization data.

FIELD OF THE INVENTION

The present invention relates to digital radio communication systems, ingeneral, and to automatic creation of emergency talk group, inparticular.

BACKGROUND OF THE INVENTION

Two-way wireless communication systems include a plurality of mobilestations (MSs), a limited number of wireless communication resources (orcan be built without an infrastructure), and a communication resourcecontroller.

Digital addressing used in these systems allows for partitioning of theplurality of MSs into talk groups. Mobile stations arranged in talkgroups usually have a similar function or geographic location howeverother basis for partitioning is also possible. A mobile stationinitiating a talk group call to other mobile stations within its talkgroup such that the other members will receive the communicationsimultaneously. Selection of talk group programmed into the mobilestation allows the user to select and operate on one of many possibletalk groups at any instant in time. This functionality of talk groups isimportant and very useful especially in public safety applications.

Ability of simultaneous communication with plurality of other MSs isparticularly important in emergency situations.

One method of controlling operation of mobile stations known in the artis to rely on a dispatcher. Verbal or text messages are broadcasted fromthe dispatcher to all mobile stations in the talk group. In emergencysituations, e.g. in case of an accident it takes time for the dispatcherto create a talk group and to assign as well as communicate the messagesto the personnel closest to an incident. Such method causes some delayas usually additional exchange of information is required.

SUMMARY OF THE INVENTION

There is a need for a method of automatic creation of a talk group in adigital radio communication system and for a mobile station for use insuch communication system, which alleviate or overcome the disadvantagesof the prior art.

According to a first aspect of the present invention there is thusprovided a method of automatic creation of a talk group in a digitalradio communication system as claimed in claim 1.

According to a second aspect of the present invention there is thusprovided a mobile station for use in a digital radio communication asclaimed in claim 18.

The present invention beneficially allows for short-cutting the manuallyprocess of coordinating a dispatch in response to an emergency message,by immediately and automatically creating a talk group which may providesupport to the unit sending the emergency message and automaticallyadding the closest emergency service unit (or units) to the dynamicallycreated talk group.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be understood and appreciated more fully fromthe following detailed description taken in conjunction with thedrawings in which:

FIG. 1 is a schematic illustration of a communication system operatingin accordance with one embodiment of the present invention,

FIG. 2 is a flow chart illustrating a method of automatic creation of atalk group in a first embodiment of the present invention,

FIG. 3 is a flow chart illustrating a method of automatic creation of atalk group in a second embodiment of the present invention,

FIG. 4 is a flow chart illustrating a method of automatic creation of atalk group in a third embodiment of the present invention,

FIG. 5 is a flow chart illustrating a method of automatic creation of atalk group in a fourth embodiment of the present invention,

FIG. 6 is a block diagram of a mobile station in one embodiment of thepresent invention.

DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

The term a dispatch centre herein below refers to a specialized radiocommunication unit, preferably equipped with additional computeroperated support units, which is adapted to control at least portion ofmobile stations of a communication system

The term infrastructure herein below refers to hardware and softwareelements that forms a communication network and allow for transmittingvoice and/or data over the radio channel(s).

Referring to FIG. 1 one embodiment of a wireless communication system100 according to the present invention is shown. The communicationsystem comprises a plurality of mobile stations (MSs) 102-116, adispatch centre 148 and an infrastructure 120, 136-146, which allows forcommunication in trunking mode as well as in direct mode. Alternativelythe communication system 100 may comprise only the plurality of MSs102-116 and said dispatch centre.

The invention allows for automatic creation of a talk group in awireless communication system 100 in a situation when a user of one ofsaid MSs 102-116 is in an emergency situation or is a witness of anemergency situation (e.g. a car accident).

With reference to FIG. 2 and FIG. 6 one embodiment of a method ofautomatic creation of a talk group according to the present invention isshown. When a user of a first mobile station 102 is in an emergencysituation and presses a dedicated button on the first MS 102 anemergency message is transmitted over the air 200 on a broadcastchannel. Said emergency message contains at least an ID of the mobilestation 102, identification that this is an emergency message andcurrent geographical localization of the transmitting MS. Said emergencymessage may optionally contain a short indication what type of emergencyservice is required (e.g. police, an ambulance, a fire brigade, etc).Transmitting this additional information could require manual typing bythe user or choosing from the list stored in a memory 612 of the MS 600.Other mobile stations 104-116, after receiving said message,automatically transmit 202 their IDs and localization data also on saidbroadcast channel. In a next step 204, 206 those MSs which transmittedtheir IDs and localization data and are located within a predefineddistance D1 from said first mobile station 102 are selected to a talkgroup.

Alternatively all MSs that replied to said emergency message areselected to said talk group.

If there is no MS within said predefined distance or the number of MSswithin said predefined distance is too small 208 said predefineddistance D1 is increased 216 to D2 and other MSs located within distanceD2 are selected to said talk group.

In one embodiment said selection 204, 206 is performed by said firstmobile station, which is equipped with a microprocessor 610 and a memory612. Said IDs and localization data received in response to saidemergency message are stored in said memory 612 and said microprocessor610 is adapted to calculate the distances between said first mobilestation and any one of said other mobile stations which have respondedto said emergency message and then create a talk group comprising othermobile stations based on said calculated distances. This embodiment isapplicable to communication systems without an infrastructure or to asituation when infrastructure is not used.

Alternatively for a communication system with an infrastructure saidstep of selecting MSs to said talk group is performed by saidinfrastructure 120, 136-146.

When said talk group is created or at the time of selecting said MSs tosaid talk group an emergency service unit 118 is localized 210 andselected 212 to said talk group. The emergency service unit 118 closestto said first mobile station is selected even if its distance is biggerthan the predefined distance D1. If the emergency situation requires itis possible that more that one emergency service unit is selected tosaid talk group.

For communication systems with said infrastructure 120, 136-146 adispatch centre 148 transmits driving directions to said emergencyservice unit (or units) 118.

Referring to FIG. 3 and FIG. 6 a second embodiment of a method ofautomatic creation of a talk group according to the present invention isshown. When a user of a first mobile station 102 is in an emergencysituation and presses a dedicated button on the first MS 102 anemergency message is transmitted over the air 200. Other mobile stations104-116, after receiving said message, automatically transmit 202 theirIDs and localization data but only if they are localized within apredefined distance D1 from said first mobile station. If there isresponse from said other MSs 304 a talk group is being created 206. Ifthere is no other mobile station within said predefined distance D1 fromsaid first mobile station 304 said other mobile stations, which distancefrom said first mobile station is larger than said predefined distanceD1, transmit their ID and localization data 306 in response to saidemergency message. As the emergency message and the responses aretransmitted on the broadcast channel said other MSs listen to messagestransmitted over the air and they know that no response was transmittedto said emergency message. They reply if there was no response fromwithin D1 within a predefined period of time.

In alternative embodiments said response messages can be transmittedalso over a dedicated channel.

After creation of said talk group or at the time of selecting MSs tosaid talk group, which can be done in the same way as in case of thefirst embodiment described above, a closest emergency service unit (orunits) 118 is localized 210 and selected 212 to said talk group.

For communication systems with an infrastructure 120, 136-146 a dispatchcentre 148 transmits driving directions to said emergency service unit(or units) 118.

For communication systems with infrastructure said selection 304, 206,210, 212 is being done by said infrastructure or by a dispatch centre148 and for communication systems without infrastructure or wheninfrastructure is not used said selection is being done by said firstmobile station 102.

With reference to FIG. 4 and FIG. 6 a third embodiment of a method ofautomatic creation of a talk group according to the present invention isshown. When a user of a first mobile station 102 is in an emergencysituation and presses a dedicated button on the first MS 102 anemergency message is transmitted over the air 200 on a broadcastchannel. Other mobile stations 104-116, after receiving said message,automatically transmit 202 their IDs and localization data but only ifthey are localized within a predefined distance D1 from said firstmobile station. If there is no response 304 to said emergency messagesaid predefined distance is increased 402 and said emergency message istransmitted again 404. (The other mobile stations 106, 108, 114, 116located beyond said predefined distance transmit their IDs andlocalization data if they receive the same emergency message transmittedagain.) If there is a response from at least portion of said othermobile stations 106, 108, 114, 116, the talk group is being createdwhich consist of the first mobile station 102 and other mobile stationsthat responded to said emergency message.

After creation of said talk group or at the time of selecting MSs tosaid talk group, which can be done in the same way as in case of thefirst embodiment described above, a closest emergency service unit (orunits) 118 is localized 210 and selected 212 to said talk group.

For communication systems with an infrastructure 120, 136-146 a dispatchcentre 148 transmits driving directions to said emergency service unit(or units) 118.

For communication systems with said infrastructure 120, 136-146 saidselection 304, 206, 210, 212 is being done by said infrastructure 120,136-146 or by said dispatch centre 148 and for communication systemswithout said infrastructure or when said infrastructure is not used saidselection is being done by said first mobile station 102.

With reference to FIG. 5 and FIG. 6 a fourth embodiment of a method ofautomatic creation of a talk group according to the present invention isshown. When a user of a first mobile station 102 is in an emergencysituation and presses a dedicated button on the first MS 102 anemergency message is transmitted over the air 200 on a broadcastchannel. Other mobile stations 104-116, after receiving said message,automatically transmit 202 their IDs and localization data. Said othermobile stations 104-116 transmit their responses 502, 504, 506 with somedelay and the value of said delay depends on the distance from saidfirst mobile station to any one of said of the mobile stations 104-116.A relation between said delay and said distance is presented in Table 1.It is obvious that the delay may be increased in many different ways andthe one presented in Table 1 is an example only.

TABLE 1 Distance D Delay D ≦ D1 No delay D1 < D ≦ D2 T1 D2 < D ≦ D3 2 ×T1 . . . . . .

If there is a response from the other mobile stations located withindistance D1 said other mobile stations are selected and said talk groupis created 206. If there is no other mobile station 508 within distanceD1 from said first mobile station 102 other mobile stations locatedwithin distance D2 are selected and said talk group is created 206. Ifthere is no other mobile station 510 within distance D2 other mobilestations located within distance D3 are selected and said talk group iscreated 206. This procedure may be repeated as long as at least one ofthe other mobile stations will be found within some predefined distancefrom said first mobile station 102.

After creation of said talk group or at the time of selecting MSs tosaid talk group, which can be done in the same way as in case of thefirst embodiment described above, a closest emergency service unit (orunits) 118 is localized 210 and selected 212 to said talk group.

For communication systems with an infrastructure 120, 136-146 a dispatchcentre 148 transmits driving directions to said emergency service unit(or units) 118.

For communication systems with said infrastructure 120, 136-146 saidselection 508, 510, 512, 206, 210, 212 is being done by saidinfrastructure 120, 136-146 or by a dispatch centre 148 and forcommunication systems without infrastructure or when infrastructure isnot used said selection is being done by said first mobile station 102.

Alternatively for communication systems with the infrastructure, whenthe talk group is created, information on the talk group (including IDsof members of the talk group and their localization data) can betransmitted to a dispatch centre 148. After this transfer the dispatchcentre 148 takes over control of the talk group.

Importantly, an advantage of this invention is that by limiting thenumber of said other mobile stations that respond at the same time (e.g.only those MSs located within predefined distance are allowed to respondor by introducing delay for transmitting response, etc.) allows forlimitation of the risk of system congestion.

The localization data transmitted by said first mobile station and saidother mobile stations are data obtained via GPS system or calculatedbased on triangulation data. It is obvious for those skilled in the artthat other localization/positioning system's data may be used.

In those embodiments where the communication system operates in trunkingmode, said predefined distance can be limited to the borders of a cell122 or to the borders of a group of cells 124-134 within which saidfirst mobile station is located. However actual distance measured inlength units may also be applied.

It is obvious for those skilled in the art that the mobile unit can beeither a portable or mobile radio.

Referring to FIG. 6 one embodiment of a mobile station capable ofoperating in accordance with the disclosed method is depicted. Themobile station of FIG. 6 may be either a portable- or a mobile digitalor analog radio. The mobile station 600 comprises a microphone 620 whichprovides a signal for transmission by transmission circuit 602.Transmission circuit 602 transmits via Radio Frequency (RF) switch 604and antenna 606. The mobile station 600 also has a microprocessor 610and a memory 612. The mobile station 600 also comprises a display 618and keypad 616. Voice activation of the radio, or other means ofinteraction with a user, may also be implemented. Signals received bythe radio are routed by the RF switch 604 to a receiving circuit 608.The received signals are routed from the receiving circuit 608 tomicroprocessor 610 and audio processing circuitry 624 and 626. Alocalization circuitry 614, which in one embodiment may be a GPScircuitry is connected to said microprocessor 610. A dedicated emergencyswitch 622 is also connected to said microprocessor 610.

In operation said emergency switch 622 when activated initiate themicroprocessor to transmit an emergency message which contains at leastindication that this is an emergency message, ID of said mobile stationand current geographical position of said mobile station. Saidgeographical position is provided by said localization circuitry 614.When said communication 600 unit receives an emergency message saidmicroprocessor calculates distance between said mobile station andanother mobile station, which has sent the emergency message. For thesecalculations the microprocessor uses localization data received in saidemergency message and obtained from said localization circuitry 614.Depending on the result of calculations and on the embodiment of themethod according to the present invention used the microprocessorinitiate transmission of the response message (containing ID and itslocalization data) or not.

When said mobile station 600 receives messages with said IDs andlocalization data in response to said emergency message themicroprocessor 610 stores them in a memory 612. The microprocessor 610uses the data stored in the memory 612 to calculate distances betweensaid first mobile station and any one of said other mobile stationswhich have responded to said emergency message. Next the microprocessorselects to a talk group those of said other mobile stations, which arelocated within a predefined distance from the mobile station, whichtransmitted the emergency message. When the selection is completed thetalk group is created.

In any of the embodiments the dispatch centre 148 is preferably added tosaid talk group.

It is worth to emphasise that all these embodiments of the methodaccording to the present invention may be implemented in a communicationsystem with an infrastructure (for communication in direct mode as wellas in trunking mode) or without an infrastructure. In implementation ina communication system with an infrastructure selection of MSs to thetalk group is done by said infrastructure (e.g. zone controller). Saidcalculation of distance can be done by either by the infrastructure orby the MSs. When the method is implemented in a communication systemwithout infrastructure or when the infrastructure is not used thenselection of MSs to the talk group and calculation of the distances isdone by said the first mobile station (some calculations are also to bedone by the other mobile stations). It is also possible that the stepsof calculation and selection are performed by said first mobile stationand said step of transmitting directions 214 to said emergency serviceunit (or units) is performed by a dispatch centre 148.

1. A method of automatic creation of a talk group in a wireless radiocommunication system comprising a plurality of mobile stations, saidmethod comprising: transmitting by a first mobile station message,wherein said message comprises a first mobile station ID andlocalization data; transmitting by other mobile stations, a responsemessage in response to said message; creating said talk group byselecting said other mobile stations which transmitted said responsemessage.
 2. A method according to claim 1, wherein only said othermobile stations, which are within a predefined distance from said firstmobile station, transmits the response message.
 3. A method according toclaim 2, wherein for the radio communication system operating intrunking mode, said predefined distance is limited to the borders of acell within which said first mobile station is located or to a group ofcells.
 4. The method according to claim 2, wherein said other mobilestations, within a distance from said first mobile station larger thansaid predefined distance, transmit the response message only if there isno other mobile station within said predefined distance.
 5. The methodaccording to claim 2, further comprising: increasing said predefineddistance if no one of said other mobile stations responded to saidmessage; and re-sending said message.
 6. The method according to claim1, wherein said other mobile stations transmit the response message witha predefined delay and said predefined delay increases with increasingdistance from said first mobile station.
 7. The method according toclaim 1, wherein only those of said other mobile stations which arewithin a predefined distance from said first mobile station are selectedto said talk group.
 8. The method according to claim 7, wherein some ofsaid other mobile stations, which are located beyond said predefineddistance, are selected to said talk group if there is no one mobilestation of said other mobile stations within said predefined distance orthe number of said other mobile stations is below a predefinedthreshold.
 9. The method according to claim 1, wherein after receivingthe response messages of said other mobile stations, said step ofselecting is performed by said first mobile station.
 10. The methodaccording to claim 9, wherein after creation of talk group informationon said talk group, said talk group information is transmitted to adispatch centre, said talk group information includes IDs of members ofsaid talk group.
 11. The method according to claim 1, wherein afterreceiving the response messages of said other mobile stations, said stepof selecting is performed by an infrastructure device.
 12. The methodaccording to claim 1, further comprising adding at least one emergencyservice unit, determined to be located closest to said first mobilestation, to said talk group.
 13. The method according to claim 10,further comprising the dispatch centre transmitting driving directionsto said emergency service unit.
 14. The method according to claim 1,wherein said response messages include localization data of respectiveones of said other mobile stations, and werein the localization dataincludes Global Positioning System Data or triangulation based data. 15.The method according to claim 1, wherein said message is an emergencymessage and comprises an indication of a type of emergency service beingrequested.
 16. The method according to claim 1, wherein said message istransmitted to a dispatch centre, and said dispatch centre forwards saidmessage to said other mobile stations.
 17. The method according to claim16, wherein said dispatch centre is also added to said talk group.
 18. Amobile station comprising means for signal transmission, means forsignal reception, a microphone, an audio processing circuitry, a keypad,a microprocessor, a memory, a localization circuitry, and switch meansbeing adapted to broadcast of a message, said message comprisinglocalization data and an ID of said mobile station and to (ii) initiatecreation of a talk group comprising all or a subset of other mobilestations responding to said broadcast message.
 19. The mobile stationaccording to claim 18 being adapted to wirelessly receive a responsemessage directly from one of the other mobile stations.
 20. The mobilestation according to claim 19 being adapted to send its ID andlocalization data in response to the response message.
 21. The mobilestation according to claim 18 being adapted to wirelessly receiveresponses to the message directly from said other mobile stations. 22.The mobile station according to claim 18, said microprocessor beingadapted to calculate distances between said mobile station and each oneof the responding mobile stations.
 23. The mobile station according toclaim 18, said microprocessor being adapted to store in said memorylocalization data and IDs received from each one of the respondingmobile stations in respective response messages.
 24. The mobile stationaccording to claim 23, said microprocessor being adapted to calculatedistances between said first mobile station and each one of theresponding mobile stations and to select all or the subset of theresponding mobile stations for the talk group based on said calculateddistances.
 25. The mobile station according to claim 18 wherein saidlocalization circuitry is a Global Positioning System unit.
 26. Themobile station according to anyone of claim 18 said microprocessor beingadapted to calculate localization of said mobile station based ontriangulation data.
 27. An infrastructure device in a wirelesscommunications system configured to: receive, from a first mobilestation, a message, wherein said message comprises a first mobilestation ID and localization data; receive, from other mobile stations,response messages transmitted by the other mobile stations in responseto the message; dynamically create a talk group by selecting all or asubset of the responding other mobile stations that transmitted saidresponse messages.